I can't offer any advice but did want to say thanks for bringing this thread back up. I saw it just before going out to the hobby shop this evening and sitting there in front of me was a Revell 1:40 Corporal Missile with Transporter kit. Obviously I couldn't resist.
After opening the box and taking a look at the instructions the actual missile construction is very simple but the rest not so much. It looks like it should take a 13mm motor nicely and separate at the center for ejection of a 6 or 8" chute. Ultimately I plan to try to get this thing to launch from the model mobile launcher. I haven't built a plastic model in about 20 years (and I was about 11 or 12 then) so this could get interesting.
Yeap!
I have one setting in the basement waiting for the que! it'll likely be a 13mm conversion thou I may do some aft end rasp work to open it up for 18mm motors.
I'm also looking hard at the erector launcher vehicle and base to see what it's going to take to convert them to launch useable pieces, adding a launch rod of coarse.